JP5297310B2 - Method, system, and computer-readable medium for providing path failover for multiple SAS expanders operating as a single SAS expander - Google Patents

Abstract

A failed link is detected between a first SAS expander and a device. A data transfer of the first SAS expander connected to the device via the failed link is re-routed to a second SAS expander connected to the device via a functional link. The first SAS expander is connected to the SAS expander via the phys of the first SAS expander and the phys of the second SAS expander for inter-expander communications.

Description

This application claims the benefit of US Provisional Application No. 61 / 191,037, filed Sep. 5, 2008, which is incorporated herein by reference, under 35 USC 119 (e). This application is a co-pending application filed on the same day as this application: "COMBINING MULTIPLE SAS EXPANDERS TO PROVIDE SINGLE SAS EXPANDER FUNCTIONALITY (Single SAS) by Stephen B. Johnson, Timothy E. Hoglund, and Louis H. Odenwald, Jr. "Combine multiple SAS expanders to provide expander functionality)" (Attorney Docket No. 08-1075, Express Mail EM 260723514 US), "SPECIFYING LANES FOR SAS" by Stephen B. Johnson and Christopher McCarty WIDE PORT CONNECTIONS "(agent number 08-1461, express delivery number EM 260723505 US) and" SAS PAIRED "by Stephen B. Johnson, William Petty and Owen Parry SUBTRACTIVE ROUTING (SAS pair subtractive routing) ”(representative number 08-1513, express delivery number EM 260723528 US). All of these applications are incorporated herein by reference.

  The present disclosure relates generally to the field of serial attached SCSI, and more specifically to providing path failover when multiple SAS expanders operate as a single non-closed SAS expander. Is.

  Serial Attached SCSI (SAS) is a term that refers to various technologies designed to achieve data transfer between computing devices. The SAS protocol is a serial type that replaces the parallel type small computer system interface. In the SAS protocol, all SAS devices are either initiator devices, target devices, or expander devices. The initiator device is a device that initiates SAS data transfer, while the target device is a data transfer destination device by the initiator device. Both the initiator device and the target device are known as end devices.

  A SAS expander is a device that facilitates data transfer between multiple initiator devices and multiple target devices. The SAS protocol utilizes a point-to-point bus topology. Therefore, if an initiator device requires connection to multiple target devices, the initiator device and individual target devices must be connected to facilitate individual data transfer between the initiator device and individual target devices. Must be connected directly. Connections and data transfers between multiple initiator devices and multiple target devices are handled by the SAS expander. The SAS expander may contain a SAS device.

  A method for providing path failover while combining multiple serial attached small computer system interface (SAS) expanders to function as a single integrated SAS expander is disclosed between a first SAS expander and a device. Detecting a failed link and re-routing data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through the active link. The first SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; May be included without limitation.

  The system includes: means for combining multiple SAS expanders to function as a single integrated SAS expander; means for detecting a failed link between the first SAS expander and the device; Means for rerouting data transfer by a first SAS expander connected to a device via a link to a second SAS expander connected to the device via an active link, wherein the first SAS expander is Means for connecting to the second SAS expander through the physical port of the first SAS expander and the second SAS expander for inter-expander communication.

  The computer-readable medium is a computer-executable for implementing a method for providing path failover while combining multiple serial-attached small computer system interface (SAS) expanders to function as a single integrated SAS expander. The method includes detecting a failed link between the first SAS expander and the device and transferring data by the first SAS expander connected to the device through the failed link. Re-routing to a second SAS expander connected to the device through the first SAS expander, the first SAS expander physical port and the second SAS for inter-expander communication Through the physical port of the expander, a second SAS error It is connected to the expanders, comprising a, a non-limiting possible.

One aspect of the present invention is a method for providing path failover while combining multiple serial-connected small computer system interface (SAS) expanders to function as a single integrated SAS expander,
Detecting a failed link between the first SAS expander and the device;
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, A SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication;
With
Detecting a failed link between the first SAS expander and the device further comprises:
Detecting the failed link between the first SAS expander and the device due to at least one of a physical problem or a logical problem;
A plurality of output ports of the single integrated SAS expander including the first SAS expander and the second SAS expander are configured to share the same SAS address. .
In addition, this invention is realizable also as the following application examples.
[Application Example 1]
A method for providing path failover while combining multiple serial attached small computer system interface (SAS) expanders to function as a single integrated SAS expander, comprising:
Detecting a failed link between the first SAS expander and the device;
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, A SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication;
A method comprising:
[Application Example 2]
A method described in application example 1,
Detecting a failed link between the first SAS expander and the device further includes
Detecting a failed link between the first SAS expander and the device due to at least one of a physical problem or a logical problem.
[Application Example 3]
A method described in application example 1,
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is further connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication. ,
The data transfer by the first SAS expander connected to the device is transferred to the second SAS expander connected to the device through a valid link, and the first SAS expander for inter-expander communication Rerouting through a physical port of the second SAS expander for communication between the physical port and the expander.
[Application Example 4]
A method described in application example 1,
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is further connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication.
Linking the data transfer from the failed internal link to the physical port of the first expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication Reconfiguring the routing table of the first SAS expander to re-route to.
[Application Example 5]
A method described in application example 4,
Linking the data transfer from the failed internal link to the physical port of the first expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication Reconfiguring the routing table of the first SAS expander to re-route to
Linking the data transfer from the failed internal link to the physical port of the first expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication Reconfiguring the routing table of the first SAS expander through firmware on the first SAS expander to re-route to.
[Application Example 6]
A method described in application example 1,
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication. A method that does not indicate to a SAS initiator and a SAS target connected to the single integrated SAS expander that re-routing has occurred.
[Application Example 7]
A method described in application example 1,
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is further connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication.
The first SAS expander connected to the device through the failed internal link if the second SAS expander connected to the device through a valid internal link already has an active link to the device. Responding by arbitration progress from a panda.
[Application Example 8]
The method according to Application Example 7,
The first SAS expander connected to the device through the failed internal link if the second SAS expander connected to the device through a valid internal link already has an active link to the device. Responding from pandas via arbitration progress is
Retrying the rerouted data transfer after a while by a SAS initiator that requests the rerouted data transfer and receives the arbitration progress response.
[Application Example 9]
The method according to application example 1, further comprising:
A method comprising: in a SAS initiator connected to the single integrated SAS expander, receiving notification that the failed link exists through receipt of a CHANGE primitive.
[Application Example 10]
A method according to application example 9,
A method in which a SAS initiator connected to the single integrated SAS expander receives the CHANGE primitive and performs SAS discovery.
[Application Example 11]
A system,
Means for combining a plurality of SAS expanders to function as a single integrated SAS expander;
Means for detecting a failed link between the first SAS expander and the device;
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to the second SAS expander connected to the device through a valid link, Means for connecting a first SAS expander to the second SAS expander through a physical port of the first SAS expander and a physical port of the second SAS expander for inter-expander communication; ,
A system comprising:
[Application Example 12]
The system according to application example 11,
The means for detecting a failed link between the first SAS expander and the device further comprises:
A system comprising means for detecting a failed link between a first SAS expander and a device due to at least one of a physical problem or a logical problem.
[Application Example 13]
The system according to application example 11,
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, Means for connecting one SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; Furthermore,
The data transfer by the first SAS expander connected to the device is transferred to the second SAS expander connected to the device through a valid link, and the first SAS expander for inter-expander communication A system comprising means for rerouting through a physical port of the second SAS expander for communication between a physical port and an expander.
[Application Example 14]
The system according to application example 11,
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, Means for connecting one SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; Furthermore,
Linking the data transfer from the failed internal link to the physical port of the first expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication Means for re-establishing a routing table of the first SAS expander for re-routing.
[Application Example 15]
The system according to application example 11,
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, Means for connecting one SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; A system that does not show such rerouting to a SAS initiator and a SAS target connected to the single integrated SAS expander.
[Application Example 16]
The system according to application example 11,
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, Means for connecting one SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; Furthermore,
The first SAS expander connected to the device through the failed internal link if the second SAS expander connected to the device through a valid internal link already has an active link to the device. A system comprising means for responding by arbitration progress from a panda.
[Application Example 17]
The system according to application example 16,
The first SAS expander connected to the device through the failed internal link if the second SAS expander connected to the device through a valid internal link already has an active link to the device. Means for responding from pandas via arbitration progress are further:
A system comprising means for retrying the rerouted data transfer later by a SAS initiator that requests the rerouted data transfer and receives the arbitration progress response.
[Application Example 18]
The system according to Application Example 11, further including:
A system comprising means for receiving a notification that the failed link exists in a SAS initiator connected to the single integrated SAS expander through reception of a CHANGE primitive.
[Application Example 19]
The system according to application example 18, further comprising:
A system comprising means for performing SAS discovery upon receipt of the CHANGE primitive at a SAS initiator connected to the single integrated SAS expander.
[Application Example 20]
Computer-readable having computer-executable instructions for implementing a method for providing path failover while combining multiple serial-connected small computer system interface (SAS) expanders to function as a single integrated SAS expander A medium, the method comprising:
Detecting a failed link between the first SAS expander and the device;
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, A SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication;
A computer readable medium comprising:
It is understood that both the foregoing summary and the following detailed description are intended to be illustrative and explanatory and are not necessarily limiting of the present disclosure. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the content of the disclosure. The description and drawings together serve to explain the principles of the disclosure.

Those skilled in the art will better appreciate the numerous advantages of the disclosure by reference to the accompanying drawings.
FIG. 2 is a block diagram illustrating a SAS topology, showing a single integrated SAS expander. FIG. 6 is a block diagram illustrating various configurations of a single integrated SAS expander. FIG. 6 is a block diagram illustrating various configurations of a single integrated SAS expander. FIG. 6 is a block diagram illustrating various configurations of a single integrated SAS expander. FIG. 6 is a block diagram illustrating various configurations of a single integrated SAS expander. FIG. 6 is a block diagram illustrating various configurations of a single integrated SAS expander. FIG. 5 is a block diagram illustrating a single integrated SAS expander blade center switch configuration. FIG. 6 is a block diagram illustrating an inter-expander link of a single integrated SAS expander. FIG. 3 is a block diagram illustrating a failed internal link within a single integrated SAS expander. 6 is a flow diagram illustrating a method for combining multiple SAS expanders to operate as a single integrated SAS expander. 2 is a flow diagram illustrating a method for providing path failover when a link failure occurs within a single integrated SAS expander. FIG. 6 is a block diagram illustrating selecting a SAS wide port lane for data connection with a single integrated SAS expander. FIG. 5 is a flow diagram illustrating a method for designating a SAS wide port lane for data connection with a single integrated SAS expander. 2 is a block diagram illustrating a cascaded SAS topology configured to implement paired subtractive routing. FIG. It is a figure which shows the table | surface which showed the vendor specific function, command, and descriptor of a pair subtractive port. It is a figure which shows the table | surface which showed the vendor specific function, command, and descriptor of a pair subtractive port. It is a figure which shows the table | surface which showed the vendor specific function, command, and descriptor of a pair subtractive port. It is a figure which shows the table | surface which showed the vendor specific function, command, and descriptor of a pair subtractive port. 6 is a flow diagram illustrating a method for performing paired subtractive routing within a cascaded SAS topology.

  Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings. As reference numerals for some elements, the reference numerals with an alphabetic character added to the end are used, but when the elements are collectively referred to, the reference numerals with the additional alphabetic characters omitted may be used. is there.

  Shown is a SAS topology according to an exemplary embodiment of the present disclosure featuring a single integrated SAS expander. The topology 100 may include an initiator 110 connected to the expander 120 through narrow ports 115a ... d. The expander 120 may be connected to a single integrated SAS expander 200 through narrow ports 125a ... d. A single integrated SAS expander 200 may contain a plurality of physically separate SAS expanders 202a ... d. The SAS expanders 202a ... d may be configured to share the same SAS address in order to combine the narrow ports 125a ... d to behave as a common single wide port 150. As shown in the SAS topology 100, the narrow ports 125a ... d may be combined to form an x4 wide port 150. The SAS expanders 202a ... d may be connected to the expander 130 through narrow ports 135a ... d. The expander 130 may be connected to the target 140 through narrow ports 145a ... d. The SAS standard requires that all connections be point-to-point. However, the SAS topology 100 is compliant with the SAS standard because the wide port 150 is truly a SAS wide port.

  With reference to FIGS. 2A-2E, the integrated SAS expander 200 may include a plurality of physically separate SAS expanders 202. The SAS expander 202 may be connected to the output ports 205-244 through links 255-294. In the present disclosure, the number of SAS expanders 202, the number of ports of the SAS expander 202, the number of output ports 205 to 244, the width of the output ports 205 to 244, and the SAS expander ports used for the links 255 to 294 are described. Depending on the number, a single integrated SAS expander 200 with a wide variety of configurations is contemplated.

  The output ports 205-244 may be wide ports. The output ports 205-244 may be configured to share the same SAS address. Under the SAS standard, this defines output ports 205-244 as a single wide port of the same expander. Each output port 205-244 may be connected to all SAS expanders 202a ... h (not shown). The width of output ports 205-244 depends on how many SAS expander ports are used on links 255a ... h-294a ... h to connect to each output port 205-244. Good. Each SAS expander 202a ... h may have a plurality of SAS expander ports connected to each output port 205-244. For example, if a single integrated SAS expander 200 is connected to each output port 205-244 through links 255a ... b-294a ... b using a single SAS expander port. When the expanders 202a ... b are included, the output ports 205 to 244 are x2 wide ports. In addition, if a single integrated SAS expander 200 has two SAS expanders 202a ... b connected to each output port 205-244 through a link using two SAS expander ports. The output ports 205 to 244 are x4 wide ports. These configurations may allow simultaneous access from any port of a single integrated SAS expander 200 to any other port with full port bandwidth.

  A blade center switch configuration 301 of a single integrated SAS expander 300 is provided. Referring to FIG. 3, a plurality of CPU blades 302 may be connected to the input ports 305 to 320. The input ports 305 to 320 may be wide ports. Input ports 305-320 may be configured to share the same SAS address. Under the SAS standard, this defines input ports 305-320 as a single wide port of the same expander. Each input port 305-320 may be connected to each SAS expander 202a ... b through links 355a ... b-375a ... b. As shown in blade center switch configuration 301, input ports 305-320 use two SAS expanders 202a ... through links 355a ... b-375a ... b using one SAS expander port. x2 wide port connected to b, but other configurations are fully contemplated in these disclosures. Each SAS expander 202a ... b may be connected to each output port 205-218 through links 255a1, a2 ... b1, b2-268a1, a2 ... b1, b2. As shown in blade center switch configuration 301, output ports 205-218 are connected through links 255a1, a2 ... b1, b2-268a1, a2 ... b1, b2 using two SAS expander ports. Although it is an x4 wide port connected to two SAS expanders 202a ... b, other configurations are fully contemplated in this present disclosure. The output ports 205 to 218 may be connected to a plurality of data storage devices 303.

  The plurality of SAS expanders 202 may be configured to share the same SAS address. Under the SAS standard, this defines multiple SAS expanders 202 as a single expander. In each SAS expander 202, firmware may be executed to cause multiple SAS expanders 202 to behave and respond as a single expander. As shown in FIG. 4, each SAS expander 202a ... d may be connected to each of 202a ... d through an inter-expander link (IEL) 430-435. The IELs 430-435 may allow the SAS expanders 202a ... d to behave and respond as a single expander through communication and coordination. The IELs 430 to 435 may communicate through other management methods such as SAS management protocol (SMP), inter-integrated circuit bus protocol (I2C), extended parallel port (EPP), Ethernet (registered trademark), shared memory, or the like. The IELs 430-435 may allow the IEL domain 420 to be zoned from the primary switch domain 410. Broadcasts may be disabled in IELs 430-435 to eliminate any loop events that are not compliant with the SAS standard. The IELs 430-435 may use multiple SAS expander ports. The physical ports used for IELs 430-435 may be completely hidden from the primary switch domain. The physical port numbers used in the primary switch domain of the SAS expanders 202a ... d may be remapped to a single logical number. The IELs 430-435 allow failures to occur in any combination of SAS expanders 202a ... d while maintaining connectivity between any effectively operating SAS expanders 202a ... d. It's okay. Furthermore, any input port 305-320 and output port 205-244 can maintain connectivity with reduced bandwidth, unless all SAS expanders 202a ... d are faulty. . SMP target processing may be handled by a single master SAS expander of a single integrated SAS expander 200. Connection requests to a single integrated SAS expander 200 may be routed to a single master SAS expander through IELs 430-435. The SAS expanders 202a ... d may share SMP target processing.

  Referring generally to FIG. 6, a method for combining multiple SAS expanders is shown. For example, the method may implement techniques for connecting and combining SAS expanders as described below (and as shown in FIGS. 1, 2A-2E, 3 and 4). The method 600 uses at least one first physical port of the first SAS expander to make at least one second physical of the second SAS expander physically separate from the first SAS expander. Along with the ports, a step 602 may be included that groups together at least one common SAS wide port. For example, organizing to at least one common SAS wide port (205-244) may include assigning the same SAS address to at least one common wide port (205-244).

  The method 600 may further include a step 604 of assigning the same SAS address to the first SAS expander and the second SAS expander. The assignment of the same SAS address to the first SAS expander and the second SAS expander behaves and responds with the first SAS expander and the second SAS expander as a single integrated SAS expander 200. It may be possible to let The assignment may be performed through firmware executed on the first SAS expander and the second SAS expander. Further, the physical port numbers of the first SAS expander and the second SAS expander may be remapped as a single logical order physical port number of a single integrated SAS expander. For example, the first physical port of the first SAS expander may be remapped to fall within a first range of numbers in a single logical order, and the second number of the first SAS expander Physical ports may be remapped to fall within a second range of numbers in a single logical order.

  Method 600 may further include a step 606 of directly connecting the first SAS expander to the second SAS expander for inter-expander communication. The inter-expander communication may use SMP communication or other communication methods such as inter-integrated circuit bus protocol (I2C), extended parallel port (EPP), Ethernet (registered trademark), and shared memory. In a further embodiment, the connection (430-435) between the first SAS expander and the second SAS expander for inter-expander communication is the physical port of the first SAS expander and the second It may be implemented through the physical port of the SAS expander. Further, the physical port of the first SAS expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication are the primary switch domain of a single integrated SAS expander ( 410). For inter-expander communication between the first SAS expander and the second SAS expander, there are at least two physical ports of the first SAS expander and at least two physical ports of the second SAS expander. May be used. Further, if at least one SAS expander remains operational within a single integrated SAS expander (eg, during the failure of a SAS expander), which common SAS wide The port is also maintained operational with a reduced reduced bandwidth.

  A single integrated SAS expander 500 may be configured to provide path failover when an internal link fails within a single integrated SAS expander. Referring to FIG. 5, as described above, input ports 502-508 may be connected to each expander 202a ... d through links 552a ... d-558a ... d. Further, the input ports 502-508 may be SAS wide ports. The output ports 510-516 may be connected to each expander 202a ... d through links 560a ... d-566a ... d. Further, the output ports 510-516 may be SAS wide ports. Each expander 202a ... d may be connected to each other through a SAS expander port for inter-expander communication. As shown in a single integrated SAS expander 500, the link 566b between the SAS expander 202c and the output port 516 may have failed. Link 566b may have failed due to, for example, a physical defect. In a further example, link 566b may have failed due to a logical problem.

  Data transfers scheduled to be transmitted over the failed link 566b may be rerouted to another SAS expander connected to the output port 516. This data transfer may be rerouted to another SAS expander through a physical port used for inter-expander communication between SAS expanders. As shown in the single integrated SAS expander 500, data transfer between the SAS expander 202c and the output port 516 through the fault link 566b passes through the SAS expander 202d through the inter-expander communication link 434. May be rerouted to The data transfer may be rerouted from the SAS expander 202d to the output port 516 through the link 566c. Thus, output port 516 will receive the data transfer as originally intended, but over a different physical link. Furthermore, if the SAS expander 202d has an active link to the output port 516, the SAS expander 202c responds to the SAS initiator with an arbitration progress notification (AIP) provided via SMP. You can do it. The SAS initiator may try to transfer data after a while after receiving the AIP or OPEN rejection (retry) SMP response from the SAS expander 202c.

  In a further aspect of the present disclosure, SAS expander routing is performed by firmware running on the SAS expander to reroute the connection through the inter-expander communication link (430-435) rather than the failed link. You can reset the table. Further, a SAS initiator connected to a single integrated SAS expander may learn that link 566b has failed by receiving a CHANGE primitive. For example, the CHANGE primitive is provided by SMP. Then, the SAS initiator may perform SAS discovery provided through SMP, for example. Further, the SAS initiator may note the remaining number of active connections to the target and initiate as many simultaneous data transfers as equal to the remaining number of active connections to the target.

  Referring generally to FIG. 7, a method for providing path failover while combining multiple SAS expanders to function as a single integrated SAS expander is shown. For example, the method may implement a technique as shown in FIG. In this embodiment of the invention, the method 700 includes detecting 702 a failed link between the first SAS expander and the device. For example, a detected failed link may have failed due to a physical problem. The detected failed link may have failed due to a logical problem.

  The method 700 further retransmits the data transfer by the first SAS expander connected to the device through the failed link to the second SAS expander connected to the device through the active link (the link that is operating effectively). Routing 704 may be included. For example, a single integrated SAS expander failed link may have failed due to physical problems within the failed link. In another example, a failed link may have failed due to a logical problem. The first SAS expander may be connected to the second SAS expander through the physical port of the first expander and the physical port of the second SAS expander for inter-expander communication. In a further embodiment, the rerouting of the data transfer by the first SAS expander connected to the device through the failed link to the second SAS expander connected to the device through the active link is the communication between the expanders. May occur through the physical port of the first expander for communication and the physical port of the second SAS expander for inter-expander communication. In an exemplary embodiment, the rerouting of the data transfer includes data transfer from the failed internal link to the physical port of the first expander for inter-expander communication and the second SAS for inter-expander communication. Reconfiguring the routing table of the first SAS expander to reroute to the link to the expander's physical port may be included. For example, the reconfiguration of the routing table of the first SAS expander may be performed through firmware executed on the first SAS expander.

  The step of rerouting data transfer from a failed link in a single integrated SAS expander to a second SAS expander over a link for inter-expander communication is such rerouting has occurred. May not be shown (not notified) to SAS initiators and SAS targets connected to a single integrated SAS expander. However, if the second SAS expander currently has an active link to the device and data is being rerouted from the failed link to the second SAS expander, the device is passed through the failed link. The connected first SAS expander may respond with an AIP response. In such a case, the SAS initiator that has received the AIP response may retry the data transfer after a while. A SAS initiator connected to a single integrated SAS expander may be notified about the failed link through receipt of a CHANGE primitive. Upon receipt of the CHANGE primitive, the SAS initiator may perform SAS discovery. For example, SMP provides SAS discovery including SAS discovery and a SAS discovery response.

  A SAS initiator specified data connection configuration 800 is provided. Referring to FIG. 8, the SAS initiator 810 may be connected to the SAS expander 820 through the SAS wide port 880. At least one physical port of the SAS expander 830 and at least one physical port of the SAS expander 840 may be combined into a common SAS wide port 890. In order for SAS expander 830 and SAS expander 840 to operate as a single integrated SAS expander, SAS expander 830 may share the same SAS address as SAS expander 840. The SAS expander 820 may be connected to the SAS expander 830 and the SAS expander 840 through a common SAS wide port 890. The SAS expander 830 may also be directly connected to the SAS expander 840 through an inter-expander communication link via the physical port of the SAS expander 830 and the physical port of the SAS expander 840. The SAS expander 830 and the SAS expander 840 do not operate as a single integrated SAS expander, but may have a cascade connection configuration. A plurality of SAS targets 850 to 875 may be connected to the SAS expander 830 and the SAS expander 840 through a SAS narrow port. The number of SAS targets 850 to 875 may be larger than the number of physical ports of the SAS expander 830 or the SAS expander 840. For example, the SAS targets 850-875 may be a hard disk array such as a simple disk bundle (JBOD, Just a Bunch Of Disks) SAS array.

  The SAS initiator 810 may specify the lanes of wide ports 880, 890 that are used to form a data connection from the SAS initiator 810 to one of the SAS targets 850-875. Wideport 880,890 lane designations may be used for fairness control, where some lanes of wideports 880,890 are used to access SAS targets 850-875. In contrast, other lanes of wide ports 880, 890 may be used for delivery to other parts of the SAS configuration. The SAS initiator 810 may further specify a lane in the OPEN frame of the connection request. Such an OPEN frame may be provided through an SMP connection request. The SAS initiator 810 may learn the optimal lane for data connection from the SAS initiator 810 to one of the SAS targets 850-875 through the implementation of a standard SAS discovery process. The SAS expander 830 and the SAS expander 840 are configured to respond through an SMP discovery response with an optimal lane for data connection from the SAS initiator 810 to one of the SAS targets 850-875, along with the SAS targets 850-875. May be. Each SAS expander in the data connection between the SAS initiator 810 and one of the SAS targets 850-875 checks the OPEN frame of the connection request from the SAS initiator 810 for the allowed lane for data connection, and is designated Data connections may only be made over those lanes.

  Referring generally to FIG. 9, a method for designating SAS wide port allowed lanes for data connection between a SAS initiator and a SAS target within a SAS domain, in accordance with an exemplary embodiment of the present disclosure, is provided. It is shown. In this embodiment of the present disclosure, the method 900 includes a step 902 of finding an optimal lane of at least one SAS wide port for data connection. For example, the SAS initiator 810 may discover the optimal lane for data connection through performing a standard SAS discovery process. Further, the SMP discovery response may be used to communicate to the SAS initiator 810 the optimal lane for data connection.

  The method 900 may further include a step 904 of specifying allowed lanes for data connections within each level of the SAS wide port in the SAS domain. For example, an allowable lane for data connection may be specified through a SAS initiator connection request. The allowable lane for data connection may be further specified in the OPEN frame of the SAS initiator connection request.

  The method 900 may further include a step 906 of checking for a specified allowed lane for data connection. For example, upon receiving the OPEN frame for the SAS initiator connection request, the SAS expander (820 to 840) may check the OPEN frame for a specified allowable lane for data connection.

  The method 900 may further include a step 908 of forming a data connection over the specified allowable lane. For example, a SAS expander may form a data connection over a specified allowed lane. Further, the SAS expander may form the data connection after checking the OPEN frame of the SAS initiator connection request for the designated allowable lane.

  A SAS cascade topology is provided that uses paired subtractive routing. To use paired subtractive routing, SAS devices in the SAS topology 1000 may reference vendor specific SMP functionality. The SAS initiators 1002 to 1004 may check an SMP REPORT MANUFACTURER INFORMATION response provided through the SMP in order to check whether the vendor-specific SMP function is supported. If supported, SAS initiators 1002-1004 request their vendor-specific SMP functionality for a list of physical ports of SAS expanders 1010-1024 whose routing attributes have been changed to use paired subtractive routing. May be used to For example, the SAS initiators 1002 to 1004 may issue SMP routing attribute change physical port list report requests 1100 to the SAS expanders 1010 to 1024 of the SAS topology 1000. Upon receiving the SMP routing attribute change physical port list report request 1100, each SAS expander 1010-1024 may respond with a list of physical ports whose routing attributes have been changed through the SMP routing attribute change physical port list report response 1120. . In operation, the SMP routing attribute change physical port list report response 1120 may contain several modified routing descriptors 1140. Each modified routing descriptor 1140 may indicate one physical port of the SAS expanders 1010-1024 and the modified routing attribute 1160 of that one physical port. For example, the changed routing attribute 1160 indicates that the physical port is either self-configured (SC, Self Configured), table initiator dedicated IN (TIIO, Table Initiator Only In), or table initiator dedicated OUT (TIOO, Table Initiator Only Out). May be specified. The TII may bind an input physical port only to the SAS initiator listed in the routing table for that port, and the TIOO may connect the output physical port to the SAS initiator listed in the routing table for that port. May only be tied to

  If the SMP routing attribute changed physical report list report response 1120 specifies the changed routing attribute 1160 of a certain physical port, the SAS initiators 1002 to 1004 indicate the routing attribute of the physical port provided by the SMP discovery response. Can be ignored. In one embodiment of the present disclosure, the vendor specific SMP function may report only the modified routing attributes: TIOI, TIOO, and SC. The SAS expanders 1010-1024 may have multiple ports with some process standard routing attributes (D, S, T) and some process modification routing attributes (TIOI, TIOO, SC).

  The SAS expanders 1010-1024 may be configured to have primary subtractive ports defined as IN and OUT pairs. Both the input port and the output port of a subtractive port will require the addresses of SAS initiators 1002-1004 in the routing table for that port. In addition, SAS expanders may be added secondary subtractive ports for directly connected devices. For example, an OPEN received at an input port may be used if the OPEN destination provided through SMP is not a directly connected device (eg, a device whose routing attribute is bound to a port with D) or the OPEN destination is for an input port. If it is not in the routing table, it may be sent from the output port of the subtractive port. For example, an OPEN received at an output port, if the OPEN destination is not a directly connected device (eg, a device coupled to a port with routing attribute D) or the OPEN destination is not in the routing table for the output port In the case, it may be transmitted from the input port of the subtractive port. The changed routing attribute TIOI may indicate an input port of a subtractive port. The changed routing attribute TIOO may indicate an output port of the subtractive port. OPEN may always be set as the primary subtractive port by default.

  SAS initiators 1002-1004 may be located at the top or bottom of cascaded SAS topology 1000. The SAS initiators 1002 to 1004 may be configured to enter only their own SAS addresses into the routing table of the TIOI port 1060 and the routing table of the TIOO port 1050 of the SAS expanders 1010 to 1024 of the cascaded SAS topology 1000. In addition, the SAS initiators 1002 to 1004 transfer only their own SAS addresses according to the positions of the SAS initiators 1002 to 1004 in the cascaded SAS topology 1000, and the TIOI ports 1060 of the SAS expanders 1010 to 1024 in the cascaded SAS topology 1000. It may be set to be included only in the routing table of TIOO port 1050. The SAS expanders 1010 to 1024 may execute firmware so that the SAS initiators 1002 to 1004 do not invade each other's area when setting the address to be entered into the SAS expander routing table (eg, location Independent routing table setting).

  The SAS target 1070 may issue an OPEN to one of the SAS expanders 1010-1024. One of the SAS expanders 1010-1024 may find the OPEN's destination address in the routing table for that one of the SAS expanders 1010-1024. The OPEN may then be sent to the SAS initiator indicated by the destination address. In another embodiment, one of the SAS initiators 1002-1004 may issue an OPEN to one of the SAS expanders 1010-1024. One of the SAS expanders 1010-1024 first looks for the OPEN destination address in any directly connected device. If found, the OPEN is sent to the appropriate direct connect device. If none of the directly connected devices find the OPEN destination address, one of the SAS expanders 1010-1024 may search for the OPEN destination address in the SAS expander routing table. If found, the OPEN is routed to the appropriate SAS initiator. If the OPEN destination address is not found in the SAS expander routing table, one of the SAS expanders 1010-1024 may send an OPEN from its paired subtractive port.

  Further, to perform SAS zoning within the SAS cascade topology 1000, it would be necessary to check only at the end expander in the topology. The end expander may compare the physical port destination for the directly connected device with the source zone group in the OPEN command. The comparison behaves subtractively until it reaches the device expander at the end of the zone.

  Referring generally to FIG. 12, a method for implementing paired subtractive routing within a SAS cascaded topology is illustrated. The method 1200 includes assigning 1210 input ports to the SAS expander device. The method 1200 may further include a step 1220 of assigning an output port to the SAS expander device. In the exemplary embodiment, method 1200 may further include a step 1230 of combining the output port and the input port with each other to operate as a paired subtractive port. The method 1200 may also include adding a second input port and a second output port to the SAS expander device. The second input port and the second output port may be paired in combination with each other as a secondary subtractive port.

  In an exemplary embodiment, the method 1200 may be configured such that when an OPEN command is received at an input port, the destination of the OPEN command is not the direct connection device of the SAS expander device and the destination is the routing of the SAS expander device. A step 1250 of sending an OPEN command from the output port if not in the table may further be included. Method 1200 may be used when an OPEN command is received at an output port and the destination of the OPEN command is not a direct connection device of the SAS expander device and the destination is not in the routing table of the SAS expander device. A step 1260 of sending an OPEN command from the input port may further be included. Method 1200, when an OPEN command is received at a second input port, the destination of the OPEN command is not a direct connect device of the SAS expander device, and the destination is not in the routing table of the SAS expander device. In some cases, the method may further include sending an OPEN command from the second output port. The method 1200 is configured such that when an OPEN command is received at a second output port, the destination of the OPEN command is not a direct connect device of the SAS expander device and the destination is not in the routing table of the SAS expander device. And a step of sending an OPEN command from the second input port. Further, the secondary subtractive port may operate for communication with the directly connected device of the SAS expander device. The OPEN command may be set as a primary subtractive port by default.

  In an exemplary embodiment, the method 1200 may further include specifying a SAS expander subtractive port through a modified routing attribute of the vendor specific SMP function. Further, if there is a modified routing attribute of the subtractive port, the SAS initiator may ignore the SMP discovery response attribute of the subtractive port and use the modified routing attribute of the vendor specific SMP.

  In an exemplary embodiment, the method 1200 may further include a step 1240 of setting only the SAS initiator address into the routing table of the SAS expander. For example, step 1240 for setting only the SAS initiator address into the routing table of the SAS expander may be performed by the SAS expander. Further, the SAS expander routing table set by the SAS expander may be a routing table for a self-designated port. Step 1240 of setting only the SAS initiator address into the SAS expander routing table may be performed by each SAS initiator in the SAS routing topology, and any SAS initiator will only have the SAS address of that SAS initiator in the SAS expander. Set to be included in the routing table. Further, each SAS initiator may be set to enter the SAS address of the SAS initiator only in the routing table of one type of changed routing attribute port of the SAS expander. The type of change routing attribute port of the SAS expander may be determined by the location of the SAS initiator within the SAS routing topology. The SAS initiator may be located at the top or bottom of the SAS routing topology.

  In the present disclosure, the disclosed methods may be implemented as an instruction set or software readable by a device. Such software may be a computer program product using a computer readable storage medium containing stored computer code used to cause a computer to perform the disclosed functions and processes of the present invention. The computer readable medium can be a floppy disk, optical disk, CD-ROM, magnetic disk, hard disk drive, magneto-optical disk, ROM, RAM, EPROM, EEPROM, magnetic card or optical card, or any suitable for storing electronic instructions. Any conventional type may be included, including but not limited to other media. Further, the specific order or hierarchy of steps of the disclosed methods is understood to be an example of a representative approach. It is understood that the specific order or hierarchy of method steps can be reconfigured based on design priority, while remaining within the scope of the disclosed content. The scope of the appended method claims presents the various step elements in an exemplary order, and is not necessarily meant to be limited to the specific order or hierarchy presented.

  The present disclosure and many of the attendant advantages thereof are believed to be understood by the foregoing description, and the form, configuration of components without departing from the disclosure or without sacrificing any of the advantages of those elements. Obviously, various changes can be made to the arrangement. The form described is merely illustrative and the following claims are intended to cover and encompass such modifications.

Claims (18)

A method for providing path failover while combining multiple serial attached small computer system interface (SAS) expanders to function as a single integrated SAS expander, comprising:
Detecting a failed link between the first SAS expander and the device;
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, A SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication;
Equipped with a,
Detecting a failed link between the first SAS expander and the device further comprises:
Detecting the failed link between the first SAS expander and the device due to at least one of a physical problem or a logical problem;
The method, wherein a plurality of output ports of the single integrated SAS expander including the first SAS expander and the second SAS expander are configured to share the same SAS address . The method of claim 1, comprising:
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is further connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication. ,
The data transfer by the first SAS expander connected to the device is transferred to the second SAS expander connected to the device through a valid link, and the first SAS expander for inter-expander communication Rerouting through a physical port of the second SAS expander for communication between the physical port and the expander. The method of claim 1, comprising:
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is further connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication.
The data transfer from the failed link to a link between the physical port of the first expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication. Reconfiguring the routing table of the first SAS expander to reroute. The method of claim 3 , comprising:
The method wherein the reconfiguration is performed through firmware on the first SAS expander. The method of claim 1, comprising:
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication. A method that does not indicate to a SAS initiator and a SAS target connected to the single integrated SAS expander that re-routing has occurred. The method of claim 1, comprising:
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, The SAS expander is further connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication.
From the first SAS expander connected to the device through the failed link if the second SAS expander connected to the device through an active link already has an active link to the device Responding with arbitration progress. The method of claim 6 , comprising:
The first SAS expander connected to the device through the failed link if the second SAS expander connected to the device through the active link already has an active link to the device Responding with the arbitration progress from
Retrying the rerouted data transfer later by a SAS initiator that requests the rerouted data transfer and receives the arbitration progress response. The method of claim 1, further comprising:
In SAS initiator connected to the single, cohesive SAS expander, the method comprising to receive a notification that the failed link exists through the CHANGE primitive. The method according to claim 8 , comprising:
The method, wherein the SAS initiator connected to the single integrated SAS expander receives the CHANGE primitive and performs SAS discovery. A system,
Means for combining a plurality of SAS expanders to function as a single integrated SAS expander;
Means for detecting a failed link between the first SAS expander and the device;
Wherein the failed link via the data transfer by the first SAS expander connected to the device, and means for rerouting to the second SAS expander that will be connected to the device via a functional link, wherein the Means for connecting one SAS expander to the second SAS expander through a physical port of the first SAS expander and a physical port of the second SAS expander for inter-expander communication;
Equipped with a,
The means for detecting the failed link between the first SAS expander and a device further comprises:
Means for detecting the failed link between the first SAS expander and the device due to at least one of a physical problem or a logical problem;
A plurality of output ports of the single integrated SAS expander including the first SAS expander and the second SAS expander are configured to share the same SAS address;
system. The system of claim 10 , comprising:
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, Means for connecting one SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; Furthermore,
The data transfer by the first SAS expander connected to the device is transferred to the second SAS expander connected to the device through the valid link to the first SAS expander for inter-expander communication. A system comprising means for rerouting through a physical port of the second SAS expander for inter-expander communication between a panda physical port. The system of claim 10 , comprising:
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, Means for connecting one SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication; Furthermore,
The data transfer from the failed link to a link between the physical port of the first expander for inter-expander communication and the physical port of the second SAS expander for inter-expander communication. A system comprising means for reconfiguring a routing table of the first SAS expander for rerouting. The system of claim 10 , comprising:
Means for rerouting the data transfer by the first SAS expander connected to the device through the failed link to the second SAS expander connected to the device through the active link; The first SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication. The means does not indicate to the SAS initiator and the SAS target connected to the single integrated SAS expander that such rerouting is occurring. The system of claim 10 , comprising:
Means for rerouting data transfer by the first SAS expander connected to the device through the failed link to the second SAS expander connected to the device through a valid link, Means for connecting a first SAS expander to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication. In addition,
The first SAS expander connected to the device through the failed link if the second SAS expander connected to the device through the active link already has an active link to the device A system comprising means for responding by arbitration progress from. 15. The system according to claim 14 , wherein
The first SAS expander connected to the device through the failed link if the second SAS expander connected to the device through the active link already has an active link to the device The means for responding by arbitration progress from
A system comprising means for retrying the rerouted data transfer later by a SAS initiator that requests the rerouted data transfer and receives the arbitration progress response. The system of claim 10 , further comprising:
A system comprising means for receiving a notification that the failed link exists in a SAS initiator connected to the single integrated SAS expander through reception of a CHANGE primitive. The system of claim 16 , further comprising:
System comprising means for implementing the S AS Discovery receiving said CHANGE primitive in SAS initiator connected to the single, cohesive SAS expander. Computer-readable having computer-executable instructions for implementing a method for providing path failover while combining multiple serial-connected small computer system interface (SAS) expanders to function as a single integrated SAS expander A medium, the method comprising:
Detecting a failed link between the first SAS expander and the device;
Rerouting data transfer by the first SAS expander connected to the device through the failed link to a second SAS expander connected to the device through a valid link, A SAS expander is connected to the second SAS expander through the physical port of the first SAS expander and the physical port of the second SAS expander for inter-expander communication;
Only including,
Detecting a failed link between the first SAS expander and the device further comprises:
Detecting the failed link between the first SAS expander and the device due to at least one of a physical problem or a logical problem;
A plurality of output ports of the single integrated SAS expander including the first SAS expander and the second SAS expander are configured to share the same SAS address. Medium.

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